Pattern controlled milling machine



July 7, 1953 Filed Dec. 20, 1947 J. B. ARMITAGE 2,644,370

' PATTERN CONTROLLED MILLING MACHINE 5 sheets-snarl I N V EN TOR. Jup $0712??? fl arwey July 7, 1953 .1. B. ARMITAGE PATTERN CONTROLLED MILLING MACHINE 5 Sheets-Sheet 2 Filed Dec. 20, 1947 I my Z2 Wm- W w a fl fl M W 3 Y J B a A: )5 H g 5 E m I Q July 7, 1953 J. B. ARMITAGE PATTERN CONTROLLED MILLING MACHINE 5 Sheets-Sheet 3 Filed Dec. 20, 1947 m a Wm m mm k 2%. W m J 3W N N\ y 7, 1953 J. a. ARMITAGE 2,6 ,370

PATTERN CONTROLLED MILLING MACHINE Filed Dec. 20, 1947 5 Sheets-Sheet 4 IIIIIIIYiIi/IIIIIl/l/M t INVENTOR.

BY M

ly 7, 1953 J. 3. ARMITAGE 2,644,370

PATTERN CONTROLLED MILLING MACHINE Filed Dec. 20, 1947 5 Sheets-Sheet 5 INVENTOR. .firqai Z frmfiaye 7M MW J /larm y Patented July 7, i953 PATTERN CONTROLLED MILLING MACHINE Joseph B. Armitage, Wauwatosa, Wis, assignor to Kearney 8a Trecker Corporation, West Allis,

Wis., a corporation of Wisconsin Application December 20, 1947, Serial No. 792,997

1% Claims.

This invention relates, generally, to improvements in machine tools, and more particularly to improved actuating and controlling mechanism especially adapted for effecting and regulating the operation of pattern controlled machine tools.

A general object of this invention is to provide more efficient actuating and controlling apparatus for a machine tool.

Another object is to provide an improved pat" tern controlled machine tool adapted to function at maximum efficiency in machining a sur= face of irregular contour on a workpiece.

Another object is to provide a pattern controlled machine tool adapted to machine a surface of irregular contour on a cam workpiece of either the face or the barrel type with equal facility.

Another object is to provide improved auto" matic means for controlling and adjusting a var iable speed transmission of the stepless type.

Another object is to provide, in a pattern controlled machine tool, a Work carrying spindle selectively positionable either transversely of or axially parallel with a tool carrying spindle, to-

gether with automatic means for varying the relative displacement therebetween.

Another object is to provide a work carrying spindle adapted to be driven at a fast rapid traverse rate of speed or at a predeterminately varb iable rate of speed in cooperative relationship With a tool carrying support, and having tripping mechanism adjustable to selectively change the speed rate thereof.

Another object is to provide an improved pattern controlled machine tool adapted to maintain automatically a substantially constant rate of machining action regardless of the shape of the contour being machined and including adjusting mechanism effective to varylthe allowable range in which the rate of machining action is maintained substantially constant.

Another object is to provide improved automatic means in combination with independently operable manually movable means for control- 7 ling and adjusting a variable speed transmission.

Another object is to provide an improved manually operable controlling mechanism for a pattern controlled milling machine, adapted to permit single lever control of the workpiece carrying spindle at a predetermined feeding rate of speed, a fast rate of speed for positioning, or a reversal in direction of rotation at either the feed or fast rates of speed.

Another object of the invention is to provide improved selectively operable manual and power driven means for positioning the work carrying spindle relative to the tool carrying spindle in a machine of the pattern controlled type.

A further object is to provide a pattern controlled machine tool adapted to machine a groove combining any variety of helical angles in the outer periphery of an elongated cylindrical workpiece as well as to machine an irregularly shaped contour on the outer periphery of a flat circular workpiece with equal facility.

A further object is to provide an improved cutting feed mechanism in which any of various rates of relative tool and work movement may be pro-selected and maintained constant in spite of conditions normally tending to vary the feed rate in different portions of the cutting movement as, for example, in pattern controlled movements where the actual feed rate normally varies according to changes of form in the contour which is being machined.

A still further purpose is generally to simplify the construction and operation of transmission and control means for machine tools, particularly for machines incorporating some of the previously mentioned improvements, and especially for milling machines, and still other objects will be apparent from the following description taken in connection. with the claims.

According to this invention, an improved pat tern controlled machine tool for forming contoured surfaces is provided with control means functioning automatically to maintain the rate of relative feeding movement between a forming tool and a workpiece substantially constant regardless of the shape of the pattern being followed. In a preferred embodiment utilizing a rotary forming tool, the pattern is formed in the shape and size of the contour which it is desired to reproduce on the workpiece, and it is engaged by a follower roller of diameter exactly equal to that of the rotary tool. Yieldable feeding means are arranged to maintain the rotating pattern in engagement with the cooperating follower roller and, simultaneously therewith, to maintain the rotating workpiece in engagement with the rotary tool. In pattern controlled ma chine tools of the usual construction, the cutting action of the rotary forming tool upon the workpiece varies considerably with changes in the slope or angle of the contour of the pattern and its radial position, the actual feeding rate being comparatively slow at some points and very much faster at others, depending particularly upon the amount of movement occurring along steep elements of the pattern. To obviate this diffi culty, operation of the guiding pattern is coordinated with the operation of a cooperatively formed feed regulating cam that is operatively connected to adjust an infinitely variable speed transmission which directly controls the rotational feeding rate of the workpiece. Thus, as the workpiece is revolved relative to the rotary forming tool, the guiding pattern and the feed regulating cam exert a continuous and synchronous control to guide the path or cutting action generated between the workpiece and the orming tool and, likewise, to vary the rotational feeding rate for promoting a relatively uniform rate of cutting action. Guiding patterns of various shapes and sizes, and cooperating follower rollers of various diameters may be utilized in combination with appropriate feed regulating cams of the required configuration. Improved control means are provided for effecting manual control of the movement of the pattern and workpiece toward or away from the follower and out ter and for eifecting reversal in the direction of feeding movement of the workpiece relative to the cutter.

The foregoing and other objects of this inven tion, which will become more fully apparent from the following detailed specification, may be achieved by the particular pattern controlled milling machine constituting an exemplifying embodiment of the invention illustrated in and described in connection with the accompanying drawings, in which:

Figure 1 is a View in left side elevation of a pattern controlled milling machine constituting apparatus incorporating the invention in a preferred practical form;

Fig. 2 is a view in rear elevation of the work spindle head including parts of its associated supporting members;

Fig. 3 is an enlarged fragmentary view of the work spindle controlling and driving mechani m, taken in vertical section substantially along the line 3-3 in Fig. l;

Fig. 4 is an expanded, partly diagrammatic plan view showing the mechanical transmission mechanism for actuating the various movable elements of the spindle head, and part of the control mechanism therefor;

Fig. 5 is an enlarged view in vertical, transverse section of the feed rate controlling mechanism, taken generally along the line 55 in Fig. 1;

Fig. 6 is an enlarged detailed view of part of the feed rate controlling mechanism, taken in horizontal section along the line 66 in Fig. 5;

Fig. 7 is a fragmentary diagrammatic view showing a modified application of the work forming mechanism;

Fig. 8 is an enlarged detailed view of mecha nism adapted to effect and to control the movement of work spindle supporting members, taken in vertical section along the line 8-8 in Fig. 1;

Fig. 9 is an enlarged detailed frontal view of controlling mechanism adapted to effect transverse or longitudinal movement of the work spindle head with a portion of the cover broken away to show the micro-switches operably disposed therein; and

Fig. 10 is a fragmentary diagrammatic View of power transmitting mechanism for movement of the spindle head, taken in vertical, transverse section along the line Ifi-l0 in Fig. 8.

The particular pattern controlled machine tool illustrated in the drawings as exemplifying ap-.

paratus of the class adapted to be constructed and operated in accordance with the present in vention, is primarily a milling machine of the knee and column type, although it is to be run derstood that the invention may be applied to other machine tools of different construction with equal advantage.

Referring more specifically to the drawings and particularly to Figs. 1 and 2 thereof, the milling machine there shown incorporates a practical operative embodiment of improved pattern controlled contour forming mechanism to which this invention is directed, the entire apparatus being fully described herein by way of a col plete disclosure.

As shown in the drawings, the milling machine is of the horizontal, spindl knee and column type comprising essentially a base and upstanding column ii that carries in its upper central part, a horizontal rotatably journalled tool spindie 52. Beneath the tool spindle 52 there are arranged a group of superimposed relatively movable work supporting members also movably carried by the column Ii, the primary member being a knee l3 slidab-ly mounted vertical movement along the forward face it of the column. The knee I3 carries a saddle slidably mounted thereon for horizontal movement toward or from the column and that functions to carry a work supporting table I t mounted ther on for horizontal longitudinal movement transversely to the axis of the tool spindle ii. The upper surface of the table it is provided with an enlarged circular platform adapted to rotatably receive a work spindle head support 5 A spindle head it having a horizontal work carrying spindle is rotatably journalled therein, is slidably carried by the support 5 a for lateral adjustment thereon in cooperating relationship with the tool spindle 12.

Power for driving the tool spindle i 2 derived from a motor 29 mounted within the of the column H and connected through a main drive clutch (not shown) to drive an adjustable transmission mechanism, carried by a housing 2! bolted in the left side of column, and which, in turn, is directly connected to drive the tool spindle H. To adjust the rate of spindle rotation, levers 22 on the side of the ransmission housing 2| are manually movable to eifect a selective change in the driving ratio obtainable in the speed transmission. A control lever 23 carries push buttons arranged to selectively energize the drive motor 26 and the lever is manually operable to effect engagement of the main drive clutch for operably connecting the motor 223 to drive tool spindle l2 through the transmission.

With the spindle head is positioned as indicated in Figs. 1 and 2, the tool spindle i2 and work spindle 19 are in axially parallel relationship as there shown, and a cutter 26 mounted on the tool spindle I2 is in work engaging relationship with a workpiece 21 mounted on the work spindle [9. In order that the workpiece 2'! may be formed to a predetermined irregular peripheral contour by cutting action of the rotating cutter 26, the workpiece is rotated and simultaneously therewith is moved toward or away from the cutter 26. To provide for this lateral displacement of the workpiece 21 relative to the cutter 26, a pattern 28 having the same configuration as that to be formed on the workpiece 2'! is removably mounted on the work spindle 59. A follower roller 29 engageable with the irregularly contoured pattern 28, is carried by a bracket removably mounted on the spindle head support if, as shown in Figs. 1 and 2. In order to maintain a continuing engagement be-= tween the follower roller 29 and the rotating pattern 28, the laterally slidable spindle head it is urged rightwardly with yieldable force exerted by means of a vertically movable weight 3! connected thereto by a flexible cable 32 threaded over a pulley $3. The pulley 33 is carried by a supporting bracket 36 removably attached to the table IS in such manner that a direct outward horizontal pull is exerted on the spindle head is by the vertically movable weight 3h For positioning the work spindle is either axially parallel, as shown in Figs. 1 and 2, or transversely to the head it may be pivoted bodily by rotating the head support if on the circular platform provided on the upper surface of the table it. Suitable clamping bolts (not shown) adapted to receive clamping nuts 35, are provided for locking the head support I! to the table it in any of its angularly adjusted positions. To indicate the angular position of the work spindle it with respect tothe tool spindle 82, a zero mark is scribed on the upper portion of the table and appropriate indicia 3'? are provided around the outer periphery of the head support, ll.

. In order that the work spindle it? may be moved into operating relationship with the tool spindle $2,. the work supporting members are vertically movable by means of a crank (not shown) applied to a squared end 38 of a shaft protruding from the front face of the knee E3 to actuate a screw and nut mechanism or the like functioning in a well known manner to move the knee l3 vertically along the face it of the column H. Vertical movement of the knee l3 effects a corresponding vertical movement of the saddle [5, table it, head support if and spindle head I8.

To provide for manually moving the saddle it toward or away from the face N3 of the column, a hand crank (not shown) may be applied to the squared end of a shaft 39 protruding leftwardly from a bracket is which is mounted on the saddle i5. As shown in Figs. 1 and 8, the shaft 39' is operatively connected to rotate a shaft M for actuating a screw and nut mechanism in a well known manner. The inner end of the shaft 39 is provided with clutch teeth d2 normally disposed to engage complementary clutch teeth formed on a collar d3 pinned to the shaft ii. In a similar manner, the table It may be moved longitudinally on the saddle I5 by applying a hand crank (not shown) to the squared end of a shaft 54 protruding leftwardly from the bracket it and which is operatively connected to rotate a feed screw 55, as shown in Fig. 8. A

nut (not shown) is secured within the table it in a manner to have meshing engagement with the feed screw which is journalledat its outward ends in the saddle 55. Thus, rotating the feed screw within its cooperating non-rotating nut will effect the desired longitudinal movement of the table it.

To facilitate movement of the saddle i5 and the table 16 for selectively positioning the spin die head it, power operable means are also provided, the power for effecting these respective movements being derived from a motor it, as shown in Figs. 1, S and 9. For finally moving the work spindle is into the desired work engaging relationship with the tool spindle I2, manual adjustment of the spindle head supporting members is preferably employed. After the initialtool spindle I2, the spindle I j the machine.

positioning has been effected, however, with drawal or advancement of the work spindle is toward the tool spindle I2 may be more conveniently effected by power movement of the spindle head supporting members. This facilitates loading and unloading of a workpiece on the work spindle it in the interval between actual machining operations, as will hereinafter be more fully explained.

In-order to insure accurate reproduction of the pattern contour, it is necessary that the cutter 26 be of such diameter that its radius is somewhat less than the radius of the most sharp- 1y curved concave surface element to be formed on the workpiece 21. In the preferred con struction illustrated in the drawings, the pattern 25 is provided with an external guiding surface of the exact size and shape of the contour re-. quired to be formed'by the cutter on the workpiece, and the follower roller 29 is of diameter exactly equal to that of the cutter 2%. Further, the follower roller is mounted in the vertical plane of the cutter spindle i2, and the spindle head support II with the bracket 30 mounted thereon are adjusted vertically to bring the follower 29 into exact axial alignment with the cutter 26, the arrangement being such that the relationship between the cutter and the workpiece is the exact duplicate of the relationship between the follower and the pattern.

Although satisfaction of the requirements as to the size and position of the pattern and cooperating follower roller relative to the workpiece and cutter will result in accurate reproduction of the desired contour, it does not necessarily result in the 'most effective operation of In pattern controlled machines of the usual construction, the cutting action of the cutter upon the workpiece varies considerably with changes in the slope or angle of the contour of the pattern and its radial position, the actual feeding rate being comparatively slow at some points and very much faster at others, depending particularly upon the amount of movement'effected by steep elements of the'pattern. Accordingly, the speed of operation of such a machine is ordinarily so limited that the maximum feeding rate at the steepest element of the pattern does not exceed that at which the desired degree of finish is attained, with the re sult that on other elements of the work, the feeding rate is much lower than it should be and the productive capacity of the machine is thus seriously restricted.

In order to cbviate this limitation upon effi cient operation, the rotational feeding rate of the workpiece is adapted, according to the present invention, to be automatically and predeterminately varied in direct relationship with the changes in the contour of the pattern. Thus, as the controlled guiding action exerted by the follower roller 29 in combination with the pattern 28 effects a lateral displacement of the workpiece 21 relative to the cutter 25, the rotational feeding rate of the workpiece 2? is automatically andv predeterminately varied in acoordance with the relative directional changes in cutter action. To this end there is provided an infinitely variable speed transmission it con nectible to drive the work spindle l9 and adapt ed to be adjusted by mechanism actuatable by rotation of a feed regulating cam 55 removably mounted for rotation with the work spindle i9, as shown in Figs. 2 and 4. The pattern 28 and the feed regulating cam 50 are predeterminately formed. to effect a. coordinated control for guidin the path of cutting action and for adjust= ing the variable speed transmission 49 respectively, the arrangement being such that the pattern and cam are so mounted with respect to the work spindle is as to exert a continuous and synchronous control thereof and thereby promote a, relatively uniform rate of cutting action.

Power for driving the work spindle is is derived from a motor mounted on the spindle head It, as shown in Figs. 1, 2, and 4, and energizable through an electrical circuit incorporated in the machine in a well known manner. A motor shaft 5?. is arranged to transmit power from the motor 5! to drive the transmission 49 which may be of any infinitely variable stepless speed type. From an output shaft 53 of the transmission, power is transmitted through gears 54 and 55 to drive a gear integrally formed on an outer rotatable housing 5i of an overrunning clutch E8. The overrunning clutch functions in a' conventional well known manner in that power is transmitted from the rotatable housing 5? "to a central, axially concentric, separately rotatable shaft 59 by means of frictional engagement of a series of rollers 55 positionable 'therebe tween. The rollers 66 are retained in equally spaced relationship about the shaft 55 by a cage 5| which is resiliently urged in circumferential direction through action of a spring as, one end of which is secured to the cage and the other to the shaft 59. The cage Si is adapted to resilient- 1y urge each of the rollers upwardly on angularly inclined surfaces of the shaft 59 into wedging frictional engagement with an inner cylindrical surface formed within the housing 5?, thereby effecting a transfer of driving power from the housing 51 to rotate the shaft 58. This arrangement also permits the shaft 59 to be rotated at a relatively high rate of speed regardless of whether or not the housing 5'! is being rotated, since, in either case rotation of the shaft causes a. withdrawal of the rollers from frictional engagement with the housing 5?.

From the shaft 59 a bevel gear splined thereto transmits power to drive a pair of bevel gears 64 and B5, journalled on a shaft 65, in oppositely rotating directions. A clutch collar 6? splined to the rotatably journaled shaft 66 is provided with clutch teeth which may be engaged with complementary clutch teeth of either of the reversibly driven bevel gears 64 or 65, as shown in Figs. 3 and 4. A worm 59 also splined to the shaft 56 meshes directly with a worm wheel 16 keyed to an elongated bearing sleeve 'H which, in turn, is rotatably journaled in bearings 12 and 13 mounted in the spindle head it.

A control trip drum 74 also keyed to the bearing sleeve H carries a driving pin l5 arranged to be axially slidable within a bored hole formed in a driving collar 16 which is removably clamped to the spindle [9 by means of a set screw T5. The control drum is is arranged to removably receive the feed regulating cam 55). As shown in Fig. 4, the driving collar is clamped to the spindle l9 in abutting relationship to the cam to restrict any forward or rearward slidable movement of the spindle it. However, the driving collar 15 may be repositioned and reclamped to the spindle in order to permit a controlled axial slidable movement thereof.

To the end that the rotational feeding rate of of the work spindle is may be varied in accordance with the directional changes of cutting action, the feed regulating cam; 58 of an irregular peripheral contour is removably secured to the rearward face of the drum M by means of cap screws 80, as shown in Figs. 2 a and 5. A follower 81, resiliently urged leftwardly to engage the peripheral contour of the-cam 59, is of the yoke type, having two laterally extending arms 82 and 33 supported for axially slidable movement in journals 84 and 85 mounted in the spindle head 18, as best shown in Fig. 5.

A gear rack 86 integrally formed on the fol.- lower arm 83 meshes with a gear segment 81 keyed to a vertical shaft 86 which is rotatably journaled in bearings 88 carried by the spindle head. Keyed to the upper. end of the shaft 88 is a gear segment 90 that meshes with a pinion 9i journaled on a parallelly mounted rotatable shaft 92. A. tension spring 93 extending between a pin carried by the gear segment 90 and an inner wall of the spindle head i8 exerts yieldable pressure tending to rotate the gear segment 8'! in a clockwise direction which, in turn, urges the gear rack 86 and the follower yoke i l in a leftward direction, as shown in Fig. 6. Integrally formed with the pinion 9| is a circular plate 94 having a circle of equally spaced bored holes 95. The holes 95. adjacent the periphery thereof are arranged to be engaged by a plunger 96 which is supported for vertical axially slidable movement in a feed selecting dial 9'! keyed to the shaft 2. The shaft 92 is journaled for rotation in a bearing 98 and has secured to its lower end a cam 99 rotatably journaled in a bearing ltll. The cam 98 is provided with an irregularly contoured groove I62 adapted to engage a lever arm m3 which is laterally slidable to adjust the variable speed transmission 43 on rotational movement. of the cam 99.

As shown in Fig. 4, the plunger as is engaged with a selected. one of the holes formed in the plate 94 in a manner that rotational movement of the plate will effect a concomitant movement. of the dial ill, the shaft Q2, and the cam 99 to vary the position of the lever arm M3 for adjusting the output speed of the variable speed transmission 49.

In order to increase or decrease the entire range of speed changes efiectuated by the feed regulating cam 59, the plunger 96 may be disengaged from the plate 9 3 and, after being angularly adjusted, reengaged in another of the holes formed in the plate 94 to effect the desired changes in the relative angular positions of the dial 9'! and the plate 94. With the follower 8! engaging a point its on the periphery of the feed regulating cam 59, the dial 9'! and the plate 94 are preferably moved into positions of relative angular adjustment about their common rotational axis to adjust the transmission as for rotating the work spindle is at a feeding rate cal culated to produce the highest degree of cutting efiiciency on a corresponding point on the periphcry of the workpiece 2?. As the work spindle is carrying the workpiece 2? and the feed regulating cam 50 revolves in clockwise direction, from the position shown in Fig. 5, the follower 8| will be moved leftwardly to adjust the transmission 39 for driving the spindle i t at a relatively faster rate of speed. Corresponding changes in adjustment of the transmission 49 will be effected as the cam 50 is rotated through a complete revolution or cycle of movement in order to maintain a relatively constant rate of surface speed of the cutter 26 on the workpiece 27. Since the point HM on the periphery of the cam 50 is farthest from the rotational axis thereof, the

,movement thereof.

'9 slowest rate of rotational feeding movement of the workpiece 21 will be effected when the cutter 26 engages a corresponding point on the periphery of the workpiece. Assuming that the dial 9'! has been predeterminately positioned in relation to the plate 94 to adjust the transmis sion 19 for producing the lowest required rate of output speed with the follower Bi engaging the point we of the cam 58, the plunger as will then be engaged with the appropriate oneof the holes 95 for retaining the dial and plate in their re-.- spective, angularly adjusted positions for unitary movement in automatically regulating the feeding action.

To increase the relative feeding rate of the workpiece 2i and the cutter 26, the plunger 96 may be withdrawn from engagement with the circular plate 96 and the dial 9? rotated in clockwise direction until the plunger can be engaged in the next or any succeeding one of the holes 95 in the plate 9d. In practice, the feeding rate selected would be the highest possible consistent with a good machined finish on the workpiece and the maximum degree of efficient operation.

In changing the machine for milling a workpiece having a different peripheral contour, it will be necessary to remove both the pattern 28 and the feed regulating cam 50 for the purpose of substituting a pattern and cam having the necessarily different configuration. While the pattern 28 is keyed to the spindle l9 and secured thereto in the usual manner, the feed cam 56 is bolted to the rearward face of the trip drum is in a manner to form a part of the automatic feed controlling mechanism for the spindle I9. To remove the cam 50, the rearward spindle bearing it! along with its supporting yoke Hi8 may be removed from the spindle head l8 by withdrawing cap screws it, as shown in Fig. 2. The spindle driving collar the spindle It in order to withdraw the cap screws 89 for removing the feed regulating cam '59, as shown in Figs. 4 and 5. Another feed regulating cam having a different irregular peripheral contour may then be secured to the trip drum id and the machine again prepared for operation by reversing the procedure outlined.

If it is desired to perform a machining operation notrequiring a variation in the feeding rate of the work spindle it, it is not necessary to place a feed regulating cam on the trip drum Mr Although the follower yoke 8i will remain in the machine, it will be resiliently urged by the spring 93 to its extreme leftward, inactive position in the absence of a feed regulating cam. With the automatic controlling mechanism thus rendered it is then removed from h inoperative, the feed selection dial 9'! may be Y manipulated to adjust the feed transmission 49 for supplying a uniform, non-varying feeding rate.

To this end, the feed selection dial 9? may be released for manual rotation independently of the circular plate M by upward movement of a knob iii; secured to the end of the axially slidable plunger 96. iii

A compression spring exert pressure against a collar H3 pinned to the plunger 96 and resiliently operates to urge both the plunger and the knob to their uppermost positions. A vertical groove H4 formed on the inner surface of a bearing sleeve I I5 is arranged to engage a pin lit extending laterally through the plunger as in a manner to limit the upward With the knob H0 in its uppermost position, and the plunger 96 disenseated in an enlarged bore H2 is arranged to 'gaged from the circular plate 94, the feed rate dial 9! is locked against free rotation. For this purpose a spring H1 clamped at its inner end between the feed dial 9? and a hub H3 is so arranged that its outer, vertically movable end iii! to its lowermost position will efiect engagemerit of the plunger with one of the holes 95 in the cam actuated circular plate. es. To retain the plunger 96 in engagement with the plate 98, the knob i it may be given a one quarter turn in either direction in such manner that the pin I it will engage a circular groove E20 formed on the inner surface or the bearing sleeve 3 l5 and intersecting the lower end of the vertical groove H4. Conversely, the plunger 96 may be disengaged from the circular plate 9% by rotating the knob iii] to again align the pin lit with the vertical groove lid, and allowing the spring"! H to urge the plunger upward. To manually rotate the feed dial 9? for directly adjusting the feed transmission 59, both the plunger 98 and the lock spring lli may be retained in disengaged position by holding the knob I iii in a position midway between its upper and lower limits of movement.

For eifecting independent selective reversal of the direction of power movement of the work spindle, there is providing at the left side of the spindle head [8, a spindle controlling lever 12! that is adapted for leftward or rightward pivotal movement from a neutral position as well as for pivotal movement toward or away from the spindle head it. As shown in Figs. 3 and l, the lever l2i has formed toward its lower end an enlarged spherical portion adapted to fit within a hollow cylindrical cavity formed within a block E22 that in turn is secured to a hollow shaft H23 rotatably journalled withinthe spindle head it. A pin 524 secured to the block I22 and extending transversely through the enlarged portion of the lever I21, operates as a pivot upon which the lever may be tilted to its forward or rearwardteeth on a shifter fork l2! slidably mounted on a bar H8. The shifting fork i2? is provided with a shoe i29 operating in a peripheral groove .of

the reversing clutch spool 61. When the lever [2| is in the central neutral position shown in Fig. 3, the clutch spool (ii is disposed in a neutral position out of engagement with the reversing bevel gears 64 and and whereupon the bevel gears may rotate on the shaft 65 without effecting rotational movement thereof. With the driving motor 5! energized, both the drive shaft 59, the bevel gear 63 and the reversing bevel gears [t -land 65 will be rotated at the selected feeding rate as herein'oefore explained and as shown in Figs. 3 and 4. When the lever lZl is in the forward position and is moved selectively to the left or right, the clutch spool 61 will be engaged to effect rotation of the work spindle it at feeding rate in either clockwise of counterclockwisedirection respectively. In order to retain the lever iii in either leftward, neutral or rightward position,'a gear segment is!) secured to the hollow shaft I23 is arranged to engage a resiliently actuated detent plunger I3I in a well known manner.

For effecting reversal of the direction of power movement of the work spindle I9 at a rapid traverse rate of speed, the control lever I2I may be tilted to its outward position and then pivoted either rightwardly or leftwardly to effect engagement of the clutch spool 61. Outward movement of the lever I2I operates to effect an inward movement of a rod I32 contained within the hollow shaft I23 for axial slidable movement. A pivotally mounted bell crank I33 is arranged with one arm engaging the rod I32 and the other arm engaging a transversely mounted axially slidable shifter rod I54 having pinned to its outward end a shifting fork I35. The shifting fork I35 is provided with a shoe I35 operating in a peripheral groove of a clutch spool I3? which is slidably mounted on the rotatable drive shaft 59. A rapid traverse clutch I38 of the frictional disk type is provided with outwardly extending pivotal fingers Its arranged to be actuated by the clutch spool I37 in a well known manner.

Power for driving the outer rotatable housing of the rapid traverse clutch I38 is derived from a gear I that in turn is driven by a gear I4! mounted directly on the motor drive shaft 52. A rightward movement of the clutch spool I37, as induced by an outward movement of the lever I2I, will effect engagement of the clutch I38 to rotate the shaft as and the bevel gear 63 secured thereto at a rapid traverse rate of speed. Thus, a movement of the lever I2! to its outward position and thence either rightward or leftward effects a sequential engagement of the rapid traverse clutch I38 and the clutch spool 67 to rotate the work spindle I9 at the fast or rapid traverse rate of speed in either selected direction.

Manual rotation of the work spindle I!) may be effected whenever the control lever I2I is in neutral position by applying a hand crank (not shown) to a squared end I43 of the vertical shaft 66 extending upwardly from the spindle head I8, as shown in Figs. 2 and 3.

For controlling rotational movement of the work spindle I 9 automatically, there are provided a plurality of trip dogs I44 adjustably position= able in a peripheral T-slot formed in the control drum I4 and disposed to engage an arm I45 secured to a rotatably journalled trip shaft MI, as shown in Fig. 4. The trip shaft I4? is provided with an outwardly extending portion having keyed thereto an outwardly slidable hollow shaft I48. The slidable shaft I45 has secured to its inner end a gear segment I43 arranged to be resiliently retained in engagement with a rack I formed on the axially slidable shifter fork I21. With the work spindle I9 being operated at feeding rate, the trip dog I44 may be positioned on the trip drum 14 in a manner to stop spindle rotation at any predetermined point. Rotational actuation of the shaft I4! as effected by the trip dog I44 operates to rotate the gear segment I49 for moving the shifter fork I21 and the clutch spool 67 to neutral disengaged position, and incidentally operates to return the control lever I2I to its neutral position. In the event a particular machining operation requires continued feeding movement of the spindle I9 beyond the point where the trip dog I44 has been predeterminately positioned to stop rotation, the hollow shaft I43 may be moved outwardly by means of a knob I5I secured thereto in a manner that the gear segment I49 is momentarily disengaged from the shifter fork rack I50 to prevent "movement of the clutch spool 61 to the neutral position.

In addition to the machining of periphery or face cams as hereinbefore described, the mechanism embodying this invention is also adapted for machining cams of the barrel type. As shown in Fig. '7, which diagrammatically portrays this application of the invention, a workpiece I52 is mounted on the forward portion of the work spindle I9 in position to be engaged by a cutter I53 mounted "on the spindle I2 A barrel type cam I54 having a peripheral cam track I55 of the shape to be formed on the workpiece I52 is mounted on the rearward portion of the spindle within the spindle head I8. In order to position the cam I54 on the work spindle I9, it is necessary to remove the bearing supporting yoke I99, the drive collar I6, and feed regulating cam 50 as hereinbefore explained and as shown in Figs. 2 and 4. With the feed regulating cam 50 removed, the driving collar It may then be re"- clamped t'o the spindle I9 "in a manner to permit axial slidable movement thereof while still retaining engagement with the driving pin 15. After the barrel type cam pattern I54 has been placed in position on the work spindle I3, with a key locking it against rotation, the yoke I08 may again be 'reclamped to the spindle head "It.

A's shown in Fig. 7, a bracket I 55 having a hardened follower pin I5! secured thereto is secured to an inner fa'ce of the spindle head IS in a manner that the pin I51 engages the peripheral track I55 of the cam I54. A T-slot (not shown) provided on an inner wall of the spindle head It and formed para-llelly with the spindle I9 is arranged to receive a clamping bolt (not shown) which the bracket I56 and pin I51 may be adjustab ly positioned in relation to the cam pattern I54. With the bracket I56 clamped in adjusted position as shown in Fig. '7, engagement of the follower pin I57 with the peripheral track of the pattern I54 will effect controlled axial movement of the work spindle I9 whenever the spindle is rotated, in a manner that cutting action of the cutter I53 on the workpiece I52 will machine therein a peripheral "groove oi tr'ack of predetermined form.

In milling a cam workpiece of the barrel type as illustrated in the drawings, the power for axially moving the work spindle I9 is supplied by the rotative movement thereof. The hardened follower pin I57 is ground to precise limits to retain an extremely close sliding fit within the parallel, opposed faces of the cam track I55. Reversal in the direction of axial movement of the work spindle I9 is thus efiected when the driving pressure exerted against the pin I57 is shifted from one face of the cam track I55 to the other.

In the event it is necessary to utilize a pattern of the open leader type, instead of one having a closed leader as shown in Fig. 7, only one guiding face of the peripheral groove will be available to contact the stationary follower pin I57 in order to control the axial slidable movement of the work spindle I 9. It is then necessary to 'urg'ethe work spindle I9 rightwardly to retain the irregular face of the cam in guiding relationship with the follower pin I51. To this end the rightward end of the work spindle I9 is provided with a separately rotatable bracket I53 to which the flexible cable 32 may be secured as is shown in Figs. 1 and 2. The cable 32 being threaded over the pulley 33 'journalled in the rem'ovably positionable bracket 34 has secured to its lower "13 end the weight 3 I serving to urge the work holding spindle rightwardly in manner to retain the one guiding face of an open leader barrel cam in a guiding relationship with the follower pin As hereinbefore explained, power operable means are also provided for moving the spindle head It either longitudinally or transversely to the column I I, as shown in Fig. 1. For this purpose, control levers its and I66 mounted on the housing bracket to at the leftward end of the saddle it are manipulable for effecting'longitudinal movement of the table I6 or transverse movement of the saddle I'5 respectively, as shown in Figs. 1 and 9. The mechanism for effecting power operable movement including the driving motor 46 is contained within the housing bracket do as is more clearly shown in Figs. 8 and 10. Ihe pivotally mounted control lever I59 being resiliently returnable to a neutral position is leftwardly movable to effect leftward movement of the table It and rightwardly movable to effect a corresponding rightward movement of the table. In a similar manner, the control lever Itll is leftwardly or rightwardly movable from the neutral position to effect inward or outward movement of the saddle I respectively. Movement of either the lever IM! or the lever It!) operates to energize the reversible driving motor 45 and simultaneously therewith to actuate clutching mechanism for transmitting driving power from the motor 46 to selectively move either the saddle It or table It.

The driving motor 46 is adapted to drive a ver= tical multiple worm shaft Iti journalled in the i bracket 38 and having meshing engagement with worm wheels I52 and I53 which are rotatably journalled on a drive shaft 4! and the table feed screw 25 respectively, as shown in Figs. 8 and 10. A collar H55 having axially splined engagement with an extension of the feed screw s5 is provided with clutch teeth Hit-adapted to engage complementary clutch teeth formed-on the hub of the worm wheel I63. A pivotally mounted bell crank I61 is arranged with one of its arm engaging a peripheral groove in the collar I65 and the other pivotally connected by means of an interconnecting link I58 to an arm I59 that in turn is keyed to a control lever shaft I'lfi. Thus a pivotal movement of the shaft IIll in either a rightward or leftward direction operates to pivot the bell crank I61 which in turn effects leftward movement of the clutch collar I65 into engagement with the worm wheel E63. To retain the collar I65 and the shaft I'it in a neutral disengaged position as shown in Fig. 8, a detent plunger I12 is urged rightwardly by means of a spring I13 to engage a V-shaped notch in the bell crank It].

In addition to effectingclutch engagement of the collar I55 to the worm wheel W53, a pivotal movement of the lever I59 rotates the shaft I19 to effect energization of the drive motor dB for either clockwise or counterclockwise rotation. To this end, a pair of micro-switches I'M and I75 are secured within the bracket 40 in a manner to be selectively actuated by a cam Il s keyed to the rotatable shaft I'Ill, as shown in Fig. 9. The electric switches I13 and [T5 are individually connected in a well known manner to energize the motor 55 for rotation in a forward or reversed direction respectively. When the lever I59 and shaft Ilfi are in the neutral inactive position, the cam I16 is also arranged to be in a neutral posi- .tion midway between the switch actuating buttons Ill and I18. Thus a leftward movement of l4 the lever I59 will rotate the cam I16 to actuate switch I for energizing the motor 46 in a re- I versed direction of rotation, and simultaneously therewith, eifect engagement of collar I55 to the worm wheel I63, thereby causing a power rotation of the feed screw $5 for effecting leftward longitudinal movement of the table.

In order to prevent the outer squared end of the manually rotatable stub shaft it from rotating at a high rate of speed whenever the table It is power operated, manipulation of the control lever I59 is also arranged to effect disengagement of the shaft 44 from the feed screw 5.

To this end, the detent plunger I'I2 has pinned to its outer end a fork I arranged to engage a peripheral groove formed on the stub shaft 44% in a manner that an outward movement of the plunger I12 will effect a corresponding movement of the stub shaft 45. This in turn efiects a disengagement of clutch teeth 12 carried by the stub shaft M. from the collar 53 pinned to theouter end of the feed screw at. As shown in Fig. 8, the manually rotatable stub shaft 34 is clutch engaged with the feed screw 35 whenever the detent plunger is in its resiliently urged inward position with the conical end thereof engaging the V-shaped notch in the bell crank Itl. Manipulating the control lever Its tov rotate the shaft I'iill for effecting power actuated longitudinal movement of the table IS as hereinbefore explained, operates to pivot the bell crank Iel with a resultant lateral movement of the notch located therein acting to move the detent plunger I72, the fork Ifid and the stub shaft Il9 outwardly. On releasing the control lever I59, the resiliently urged rightward movement of the detent plunger I72 operates to return the bell crank I61 to a neutral position and simultaneously therewith to move the stub shaft M rightwardly into clutch engagement with the table feed screw .45. i

To provide for transverse power actuated movement of the saddle I5, the control lever I53 is pivotally operable to actuate control mechanism generally similar to that employed for obtaining power movement of the table I B. This mechanism comprises a rotatably journalled shaft IZII, an arm I82 keyed thereto, a link I83 and a pivotally mounted bellcrank I84. A clutch collar I85 is carried in slidably splined engagement on the shaft t! for leftward movement into driving engagement with the worm wheel IE2 or for rightwardmovement into a disengaged position as effected by a selective pivotal movement of the bell crank it. With the clutch collar I85 in the neutral disengaged position shown in Fig. 8, a detent plunger IE6 will engage a notch in the bell crank itli will then be in a resiliently urged rightward position. A fork $81 carried by the plunger its will also be urged rightwardly to effect movement of the stub shaft 39 into clutching engagement with the collar -43 pinned to the shaft The rotatable shaft I8I also carries a cam its which is selectively movable to actuate either of two micro-switches I and IBI connected to energize the drive motor to for clockwise or counterclockwise rotation, as shown in Fig. 9.

From the foregoing "explanation of the corn struction and operation of a preferred embodimerit of the invention, it is apparent that the invention has provided an improved machine of simplified construction for the eflicient production of a wide variety of cam or like workpieces. Adjustments'necessary when changing from the milling of one specific type of workpiece to another may be made with speed and facility, substituting a pattern of the required irregular contour and a cooperating cam of irregular contour to insure duplicating the correct configuration on the workpiece to be milled with a consistently high standard of efficiency and finish on the machined surface.

Although only one embodiment of the invention has been shown and described, it will be apparent to those skilled in the art to which this invention relates, that various modifications in the manner of constructing the machine may be effected without departing from the spirit and scope of the invention as defined in the subjoined claims.

The principles of the invention having now been fully explained in connection with the fore= going description of embodying structure, I here by claim as my invention:

1. A cam milling machine comprising a column, a spindle rotatably journalled in said column, a knee slidably mounted on said column, a saddle slidably mounted on said knee, a table 'slidably mounted on said saddle for longitudinal movement thereon, a support element rotatably mounted on said table, a headstock slidably mounted on said support element, a work carrying element rotatably journalled on said headstock, a pattern of predetermined irregular peripheral contour remo'vably affixed to said work carrying element and rotatable therewith, follower means adapted to coact with said pattern to effect movement of said work spindle relative to said work carryingelement for forming a predetermined peripheral contour on a workpiece mission or said rapid traverse transmission means to drive said spindle and including tripping means operatively connected to actuate said control means for 'predeterminate operation.

In 'a pattern controlled milling machine, a frame, a cutter carrying spindle journalled in said frame, a table slidably mounted for lon-= gitudinal movement on said frame, a headstock rotatably mounted on said table, a work carrying spindle journalled in said headstock, a pattern of predetermined contour adapted to be mounted on said spindle for rotation therewith,

a follower roller adapted to engage said pattern to eifect'movement of said work spindle relative to said cutter for guiding said members in form= ing a workpiece with a peripheral contour substantially the same as said pattern, a feed regulating cam adapted for movement with said workpiece spindlaa cam follower slidably mounted in saidheadstock arranged to be moved by said feed cam, a variable speed transmission connected to drive said workpiece spindle, a manually movable control lever connectible to adjust said trans- -mission, and control means actuatable by mvem'ent of said cam follower connected to automatically adjust saidspeed transmission, where- '16 by the rotational feed rate of the workpiece is coordinately controlled in relation to the changing peripheral contour to be formed thereon to effect a relatively constant cutting action at any point on the periphery of the workpiece.

3. In a machine tool; a frame; a table slidably mounted on said frame; a shaft operatively connected to actuate said table; and controlling means operable to rotate said shaft for moving said table on said frame; said controlling means comprising a stub shaft clutch engageable with said shaft to effect manual rotation thereof, resilient means operative to move said stub shaft to an inactive disengaged position, a reversibly energizable motor, a gearwheel journalled on said shaft rotatably driven by said motor, a clutch element mounted on said shaft, a forward switch and a reversing switch connected to control said motor, and a manually operable pivotally movable control lever adapted to selectively actuate either said forward or said reversing switch respectively and simultaneously therewith to move said clutch element into driving engagement between said gearwheel andsaid shaft.

4. In a cam milling machine, a frame, a milling cutter rotatably mounted on said frame, a work supporting spindle rotatably mounted on said frame in cooperative relationship with said milling cutter, power actuated means operatively connected to rotate said milling cutter, variable speed power driving means operatively connected to turn said work supporting spindle at selected speed, a pattern mounted on said work supporting spindle, a follower mounted on said frame in position to cooperate with said pattern in guiding the action of said cutter upon a workpiece on said work spindle to reproduce said pattern, a feed control cam likewise mounted on said work supporting spindle for rotation with said pattern, and control means responsive to operation of said feed control cam and operative to adjust said variable speed spindle driving means in accordance therewith, whereby to regulate the rate of rotation of said work spindle in manner to effect a desired rate of cutting action between said cutter and the workpiece appropriate to each increment of said pattern being reproduced.

5. In a machine tool controlling mechanism,-a plurality of driven shafts adapted to be rotated, a manually rotatable shaft axially concentric to each of said driven shafts and selectively connectible thereto, a worm wheel rotatably vjournalled on each of said driven shafts, reversibly energizablepower means, a worm shaft arranged to transmit driving power from said power means to said worm wheels, a pivotal control lever movable in either direction from a resiliently returnable position, clutching means selectively actuataole on movement of said pivotal lever in either direction from said position to eifect a driving connection between said worm wheel and said drivenshaft, and a pair of switches operably associated with each of said-control levers in a mannor to be actuated respectively upon movement of said lever in the one or the other direction to energize said power means'for rotation in a clock wise or counterclockwise direction respectively, whereby movement of said lever in one direction simultaneously actuates said clutching means and energizes said power means to effect the desired rotational movement of said drivenshaft.

6. In a machine tool, rotary mean for holding a workpiece, means for holdin a cutting tool, a camming member shaped in conformity with the surface to be formed on the workpiece and'disposed to effect relative cooperative displacement of said rotary means for holding the workpiece and said means for holding the cutting tool, a power source, a variable speed transmission adapted to connect said power source to drive said rotary means, a power source arranged to rotate said means for holding the tool at any predetermined rate of speed, adjusting means for regulating said variable speed transmission, a second camming member rotatably operative upon movement of said rotary means and operatively connected to control said adjusting means, and disconnecting mechanism operative to regulate said adjusting means independently of said second camming member, whereby the range of effective output speed from said transmission may be continuously varied in accordance with a desired rate of metal removal from said workpiece.

7. In a pattern controlled machine tool, a tool support, a cooperating relatively movable and rotatable work support, and an automatic feed regulating transmission mechanism, said mechanism comprising a variable speed transmission, a cam adapted to be rotated by said work support, an axially slidable cam follower having agear rack integrally formed thereon adapted to be moved by said cam, intermediate gearing connected 'for actuation by said cam follower and movable to adjust said variable speed transmission whereby the rotational feed rate of said work support maybe predeterminately controlled, and a manual control lever selectively connectible to adjust said variable speed transmission.

8. In a pattern controlled machine tool, in 1 combination, a work supporting spindle, a cutter carryingmember, a pattern disposed to effect relative displacement of said spindle and said cutter carrying member, said pattern having a configuration substantially the same as that to be formed on a workpiece mounted on said spindle, a variable speed drive mechanism disposed to rotate said spindle, a feed selector manually operable to adjust said drive mechanism, a cam of predetermined configuration mounted on said spindle, means connected to adjust said feed selector in accordance with said cam, and disconnecting means operable in such manner that said feed selector may be independently manually adjusted in order to change the range of automatic adjustments effected by said cam member.

9. In a transmission and control mechanism for effecting relative movements of machine elements, a variable speed power driven mechanism operatively'connected to effect relative movement of the machine elements at a selectively varying .rate, control means operatively connected to adjust the rate of movement effected by said variable speed mechanism including a manually operable member having latching means, a movable member disposed to be engaged by said latching means in manner to retain said latching mean in adjusted relationship with said movable member, and'a speed regulating cam operatively connected to move said movable member thereby to adjust said variable speed mechanism for effecting a varying rate of relative movement of the machine elements. g

10. In a machine tool transmission and control mechanism, a rotatable member arranged to be driven at a predetermined constant speed or at a predeterminately varying speed, an

, infinitely variable speed transmission operatively connected to drive said member, control means removably connected to effect adjustment or said transmission, locking means arranged to lock said control means in predetermined adjusted position for rotating said member at a constant speed, and means for effecting mechanical adjustmentof said control means including a cam removably secured to said member, a yoke disposed .to be slidably moved by said cam and a motion transmitter selectively connectible to actuate said control means on movement of said yoke, whereby said transmission may be adjusted to rotate said member at a predeterminately varying rate. of

speed; e

11. In any apparatus for controlling the speed of a machine tool spindle, an infinitely variable speed transmission mechanism operatively connected to rotate said spindle, a rotatable shaft connected to adjust said transmission mechanism, an indicating dial secured to the outer end of said shaft for effecting movement thereof, means for efiecting manual adjustment of said dial including a plunger, said plunger being movable into a position wherein said dial may be manually adjusted and said plunger being movable into a position wherein said dial is locked in predetermined adjusted position, a circular member rotatably journalled on said shaft and presenting plunger receiving notches, said plunger being engageable with any one of said notches in said circular member in manner that said dial is movable therewith, a cam removably secured to said spindle, a yoke constituting a cam follower disposed to be slidably movedon rotational movement of said cam, and motion transmitting means interconnecting said yoke and said circular member, whereby said transmission may be adjusted manually to rotate said spindle at a predetermined constant speed or said transmission may be adjusted automatically to rotate said spindle at a predeterminately varying speed.

12. In a controlling mechanism for a machine tool, a driven shaft, a manually rotatable stub shaft axially concentric with said driven shaft, a clutch disengageably interconnecting said driven shaft and said stub shaft, resilient means normally operative to retain. said stub shaft in clutching engagement with said driven shaft, a reversibly energizable motor, a member driven by said motor, clutch mechanism arranged to effect an operative connection between said motor driven member and said driven shaft whenever said stub shaft is disconnected therefrom, a pivotal control lever movable in either direction from a resiliently returnable neutral position determined by said resilient means said resilient means being operative on movement of said lever from its neutral position to eifect disengagement of said stub shaft from said driven shaft, a pair of switches operative to energize said motor for clockwise or counterclockwise rotation, said switches being respec-:

tively actuatable on movement of said lever in one directionv or the other from its neutral position, and linkage operative on movement of said lever in either direction to actuate said clutch mechanism for effecting an operative connection betively connected to move said carriage in each path respectively, a reversible electric motor for actuating said carriage, clutches selectively engageable to connect said motor to said actuating mechanisms respectively, clutch control levers op'erativelyconnected to saidclutches respectively in manner toactuate eachclutch selectively upon movement of itsassociated lever in either direction .from a central neutral position, and a pair of reversing switches associated with each lever and connected to control operation of said motor in opposite directions respectively, one switch of each pair being disposed to be actuated :by its "associated leverwhen said lever is moved from'neutral in one direction and the other switch being disposed to be actuated whensaidlever is moved from neutral in theopposite direction, the arrangement being such that said carriage may be moved in either direction along either path by operation of said motor in response to actuation of the apprrnzriate lever in the selected direction.

l4.'-In a milling machine having a toolspindle, a work carrying spindle arranged for cooperative operation with said tool spindle, means for effecting bodily displacement of said work spindle relative to said tool spindle including a pattern of predetermined configuration, an infinitely variable speed transmission operativelyconnected to rotate said Work spindle, and control means connected to adjust said-transmission for rotating said work spindle at a predetermined constant rate of speed or at a predetern'linately varying rate of speed, said control means comprising a shaft connected to adjust said transmission, 'a-n indicating dial secured to said shaft, a circular control plate journalled on said shaft in coaxial relationship with said indicating dial, a plunger slidably carried by said dial for movement into engagement with said plate in manner to lock 7 said dial to said plate for movement therewith, a

feed regulating cam removably secured to said workspindle, a yoke engageable with said cam in manner to be moved thereby, .a motion transmitter interconnecting said yoke and saidplate whereby said plate will be moved to adjust said transmission for rotating said Work spindleat a predeterminately varied rate ofspeed, a lever'selectively operable to'withdraw said plunger from engagement with said plate for effecting :independent manual adjustment of said dial, and locking means operative to lock said dial in .predetermined position for maintaining said transmission in an adjusted position to rotate said work spindle at a constant rate of speed.

JOSEPH B. ARMITAGE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,119,717 Norton Dec. 1, 1914 1,716,115 Clark June 4, 1929 1,749,073 Graves Mar. 4, 1930 1,750,885 Goetz Mar. 18, 1930 1,930,722 McWhirter Oct. 17, 1933 2,010,355 Ernst et a1 Aug-6, 1935 2,047,162 .Armitage July 7,1936 2,050,127 Sassen Aug. 4, 1936 2,100,296 Wight Nov. 23, 1937 2,114,013 Ball Apr. 12, 1938 2,153,101 Schulz ,Apr. .4, 1939 2,310,878 Stephan f Feb. .9, 1943 2,379,870 I Barker July 10, 1945 2,407,913 Arrnitage Sept. 17, 1946 2,415,801 Armitage Feb. 11, 1947 FOREIGN PATENTS Number Country Date France Jan. 18, 1912 

